measure word, noun · a gathering or collection of people or objects; a crowd

他在人群中寻找他的朋友。

measure word, noun · a collection of animals, such as a herd, pack, or flight of birds

一群羊正在山坡上悠闲地吃草。

noun · an online chat group or social media group (short for 群组 qún​zǔ or 聊天 liáo​tiān群 qún)

我被拉进了一个微信群。

noun · a set equipped with a binary operation that satisfies the group axioms (associativity, identity, and invertibility) in mathematics.

李群在现代物理中有广泛的应用。